Comparative Analysis on DC Power Flow and AC Power Flow

Because of its linearity and rapidity,DC power flow is widely applied in security assessment of day-ahead generation scheduling,congestion management of electricity market,security constraints of unit commitment and economical dispatching.However,comparing with AC power flow,the error of calculation based on DC power flow and the relations among the error,network structure and operation conditions are not yet analyzed in depth.Numerical simulations for four IEEE test systems and Fujian power system were performed and quantitative indices of the error were given,and detailed analysis on the relations among the error and such factors as voltage standard deviation,reactance to resistance ratios of transmission lines and load condition was carried out.Research results showed that for the power network with reactance to resistance ratio of network components greater than 4 and the voltage standard deviation less than 0.02 the error of calculation based on DC power flow was smaller.